We put skills on about 704. Research and pumping

Despite the end of the Great Patriotic War, work on the creation of heavy self-propelled guns continued anyway. Moreover, new self-propelled guns were created as new tanks were created. So, immediately after the start of serial production of the heavy tank IS-3 at Experimental Plant No. 100, an ACS was developed, which was named ISU-152 mod. 1945 ("object 704").

This installation was created using the components and assemblies of the IS-2 and IS-3 tanks and belonged to the type of fully armored self-propelled guns with a front conning tower. In this machine, a 120 mm thick frontal plate, common for the cabin and the hull, was given an angle of inclination of 50 ° from the vertical. The lower side sheets of the felling with a thickness of 90 mm had inverse angles of inclination of 45 °. The driver was located in the conning tower at the top left and monitored through a periscopic observation device installed in the roof of the wheelhouse. The commander conducted all-round observation with the help of an MK-4 device installed in a rotating hatch cover. The other three crew members monitored using MK-4 viewing devices installed in the deckhouse roof and in the revolving landing hatch covers.
Howitzer-gun ML-20SM mod. 1944 was mounted in a frame at the front of the wheelhouse and protected by an armored mask. The length of the gun barrel was 29.6 caliber. The horizontal aiming angle was 11 °, the elevation angle was + 18 °, the declination was -1 "45". The ammunition consisted of 20 separate loading rounds. For direct fire, there was a TSh-17K telescopic sight, and from closed positions - a Hertz panorama. The direct fire range was 3800 m, the maximum - 13000 m. The rate of fire reached 1 - 2 rounds / min. Special system target designation connected the commander with the gunner and driver. The 12.7 mm DShK machine gun was paired with the gun. The second DShK machine gun (anti-aircraft) was installed on the turret of the loader's hatch. Machine gun ammunition consisted of 300 rounds.


Twelve-cylinder four-stroke Y-shaped V-2IS liquid-cooled diesel engine with a maximum power of 520 hp. at 2200 rpm. was installed in the engine compartment of the ACS. It allowed a combat vehicle weighing 47.3 tons to move at a maximum speed of 40 km / h. Compared to the tank, the shape and capacity of the fuel tanks have undergone changes. The power reserve of the installation when driving on the highway reached 220 km.
The mechanical transmission consisted of a dry-friction multi-disc main clutch, a four-speed gearbox with a range multiplier, which provided eight gears when moving forward and two - backward, two two-stage planetary swing mechanisms and two double-row combined final drives.
On each side there were six double track and three carrier rollers. Roller suspension - individual, torsion bar. Caterpillar - fine-link, pinned engagement.
The ACS was equipped with a 10-RK.-26 radio station and a TPU-4bisF tank intercom.
The ACS differed from other vehicles of this class mainly in its powerful armor protection, obtained due to the large angles of inclination of the armor plates and the unusual placement of the driver. However, the large angle of inclination of the walls of the wheelhouse, the significant recoil of the howitzer-gun barrel (up to 900 mm) and the combination of the control compartment with the combat one, significantly reduced the size of the latter and made it difficult for the crew. Placing the driver at the top led to an increase in the blind area and a deterioration in his working conditions due to the large amplitude of oscillations. This vehicle was made in one copy and is now on display at the Military Historical Museum of Armored Weapons and Equipment in Kubinka.

ISU-152 of 1945 (Object 704)- an experienced Soviet heavy self-propelled artillery installation (ACS) during the Great Patriotic War. In the name of the vehicle, the abbreviation ISU means “self-propelled unit based on the IS tank” or “IS-installation”, and the index 152 is the caliber of the vehicle's main armament. Refinement of the "1945 model" was required to distinguish the experimental ACS from the serial ISU-152.


Developed by the design bureau of experimental plant No. 100 in 1945 under the leadership of Joseph Yakovlevich Kotin, chief designer of domestic heavy tanks and self-propelled guns of that time. Unlike other experienced self-propelled guns, the ISU-152-1 and ISU-152-2, which were just non-standard rearmed production vehicles, the ISU-152 mod. 1945 was a completely new design. The adoption of the IS-3 heavy tank set the designers of the experimental plant No. 100 the task of creating an appropriate ACS based on it. Since the IS-3 was a radically revised IS-2 in terms of armor protection, the ACS based on it was also designed as an analogue of the serial ISU-152 based on the IS-2 with improved armor.

Enhanced protection was achieved both by increasing the thickness of the armor and placing it at more favorable angles to counteract the armor-piercing action of shells. The developers of the armored hull successfully coped with the task: the forehead of the installation was a continuous rolled armor plate 120 mm thick, inclined at an angle of 50 ° to the vertical. For comparison, the serial ISU-152 had frontal armor parts 90 mm thick and inclined 30 ° to the vertical. The armor of the gun mask was increased to 160 mm, and together with the armored casing of the recoil devices, the total maximum thickness of the gun's armor reached 320 mm. Due to the rearrangement of the fighting compartment, the total mass of the ACS increased by only 1.3 tons compared to the serial ISU-152. For the heavy self-propelled guns ISU-152 of the 1945 model, it had a record low overall vehicle height - 2240 mm. Among all the experienced and serial Soviet self-propelled guns during the Great Patriotic War, the ISU-152 of the 1945 model was the most protected from enemy fire. Its frontal armor was able to withstand the fire of even the most powerful German Pak 43 anti-tank gun.

The design bureau of Fyodor Fedorovich Petrov for the new SPG developed a new modification of the ML-20SM howitzer-gun, the idea of ​​which was put forward back in 1943. Its most important difference from the serial ML-20S was the absence of a muzzle brake, which made it impossible to fire from a gun in the presence of an assault force on the armor of a self-propelled gun.

However, the desire to obtain maximum security with fixed dimensions and weight turned out to be a quite expected drawback - the tightness in the fighting compartment of the self-propelled gun. The rejection of the muzzle brake in the design of the gun led to an increase in its recoil length up to 900 mm, and the favorable angles of inclination of the frontal booking required to transfer workplace driver to the left upper part fighting compartment. The field tests carried out have shown that such its location leads to a decrease in the viewable space and increased fatigue of the driver due to the large vibration amplitudes of the armored hull when the ACS moves on an uneven surface. As a result, the ISU-152 of the 1945 model was not adopted by the Red Army and was not mass-produced. The only released prototype of this self-propelled gun is currently on display at the Armored Museum in Kubinka, Moscow Region.


Description of the structure

The ISU-152 of the 1945 model had the same layout as the serial Soviet self-propelled guns of that time (with the exception of the SU-76). The fully armored hull was split in two. The crew, gun and ammunition were located in front in the armored wheelhouse, which combined the fighting compartment and the control compartment. The engine and transmission were installed at the rear of the vehicle.

Armored corps and wheelhouse

Armored corps self-propelled installation welded from rolled armor plates 120, 90, 60, 30 and 20 mm thick. Differentiated armor protection, cannon-proof. The armored plates of the cabin and the hull were installed at rational angles of inclination. The recoil devices of the gun were protected by a fixed cast armored casing and a movable cast armored mask, each of these parts had a thickness of up to 160 mm in the parts most exposed to enemy fire.

Three crew members were located to the left of the gun: in front of the driver, then the gunner, and behind the loader. The vehicle commander and the castle commander were to the right of the gun. The embarkation and exit of the crew were made through four hatches on the roof of the wheelhouse. The round hatch to the left of the gun was also used to bring out the extension of the panoramic sight. The hull also had a bottom hatch for emergency escape by the crew of self-propelled guns and a number of small hatches for loading ammunition, access to the necks of fuel tanks, other components and assemblies of the vehicle.

Armament

The main armament of the ISU-152 of the 1945 model was an ML-20SM howitzer-gun of 152.4 mm caliber with a piston bolt. The ballistics of the gun was similar to the previous version of the ML-20. A large-caliber 12.7 mm DShK machine gun was paired with the gun. The twin unit was mounted in a frame on the frontal armor plate of the wheelhouse along the centerline of the vehicle. Its vertical guidance angles ranged from −1 ° 45 ′ to + 18 °, horizontal guidance was limited to a sector of 11 °. The range of a direct fire at a target with a height of 2.5-3 m was 800-1000 m, the range of a direct fire was 3.8 km, the greatest firing range was about 13 km. The shot was fired by means of an electric or manual mechanical trigger, the practical rate of fire is 1-2 rounds per minute.

The gun's ammunition was 20 rounds of separate loading. The shells were laid along both sides of the wheelhouse, the charges were in the same place, as well as on the bottom of the fighting compartment and on the rear wall of the wheelhouse.

To protect against air attacks, the ACS was equipped with a second, anti-aircraft heavy machine gun DShK on a rotating turret at the loader's hatch with a K-10T collimator sight. Ammunition for coaxial and anti-aircraft machine guns was 300 rounds.

For self-defense, the crew had two submachine guns (submachine guns) PPSh or PPS and several F-1 hand grenades.

Engine

The ISU-152 of the 1945 model was equipped with a four-stroke V-shaped 12-cylinder V-2-IS diesel engine with a capacity of 520 hp. With. (382 kW). The engine was started with a 15 hp ST-700 electric starter. With. (11 kW) or compressed air from two tanks with a capacity of 10 liters in the fighting compartment of the vehicle. Diesel V-2IS was equipped with a fuel pump high pressure NK-1 with all-mode regulator RNK-1 and fuel supply corrector. A “Multicyclone” filter was used to clean the air entering the engine. Also, a thermosyphon heater was installed in the engine-transmission compartment to facilitate starting the engine in the cold season and heating the fighting compartment of the vehicle. The ISU-152 of the 1945 model had three fuel tanks, two of which were located in the fighting compartment, and one in the engine compartment. The total capacity of the internal fuel tanks was 540 liters. The self-propelled gun was also equipped with two external additional fuel tanks (each 90 liters), not associated with the engine fuel system.

Transmission

ACS ISU-152 of the 1945 model was equipped with a mechanical transmission, which included:
multi-disc main clutch of dry friction "steel according to ferodo";
four-speed gearbox with a range (8 gears forward and 2 reverse);
two onboard two-stage planetary swing mechanisms with a steel-on-steel dry-friction multi-disc locking clutch and band brakes;
two double row combined final drives.

Chassis

The ISU-152 model 1945 has an individual torsion bar suspension for each of the 6 solid gable road wheels of small diameter on each side. Opposite each road roller, the travel stops of the suspension balancers were welded to the armored hull. Driving wheels with removable pinion gear rims were located at the rear, and the sloths were identical to the road wheels. The upper branch of the track was supported by three small one-piece support rollers on each side. Track tensioning mechanism - screw; each track consisted of 86 single-bed tracks 650 mm wide.

Electrical equipment

The wiring in the ISU-152 self-propelled guns of the 1945 model was single-wire, the armored hull of the vehicle served as the second wire. The sources of electricity (operating voltages of 12 and 24 V) were the G-73 generator with the RRT-24 relay-regulator with a power of 1.5 kW and four series-connected rechargeable batteries brand 6-STE-128 with a total capacity of 256 Ah. Electricity consumers included:
external and internal lighting of the car, illumination devices for sights and scales of measuring instruments;
external sound signal and signaling circuit from the landing force to the vehicle crew;
instrumentation (ammeter and voltmeter);
electric triggering of the cannon;
communication equipment - radio station, target designator and tank intercom;
electrician of the motor group - the electric motor of the inertial starter, bobbins of spark plugs for the winter start of the engine, etc.

Surveillance equipment and sights

All hatches for the entry and disembarkation of the crew had Mk IV periscopic devices for observing the environment from inside the vehicle (4 in total); several more such devices were installed in the roof of the wheelhouse. The driver monitored through a special periscope device in the roof of the wheelhouse.
For firing, the self-propelled gun was equipped with two gun sights - a breaking telescopic TSh-17K for direct fire and a Hertz panorama for firing from closed positions. The TSh-17K telescopic sight was calibrated for aimed firing at a distance of up to 1500 m.However, the firing range of a 152-mm howitzer-gun was up to 13 km, and for firing at distances over 1500 m (both direct fire and from closed positions), the gunner I had to use a second, panoramic sight. To provide visibility through the upper left round hatch in the wheelhouse roof, the panoramic sight was equipped with a special extension cord. To ensure the possibility of fire in the dark, the scope scales had illumination devices.

Means of communication

Communication facilities included a 10RK-26 radio station and a TPU-4-BisF intercom for 4 subscribers. For more convenient target designation, the self-propelled gun commander had a special one-way light-signal communication system with the driver.

The 10RK-26 radio station was a set of a transmitter, a receiver and umformers (single-armature motor-generators) for their power supply, connected to the on-board power supply network with a voltage of 24 V.
10RK-26 from a technical point of view was a simplex tube heterodyne short-wave radio station operating in the frequency range from 3.75 to 6 MHz (respectively, wavelengths from 50 to 80 m). In the parking lot, the communication range in the telephone (voice) mode reached 20-25 km, while in motion it slightly decreased. A long communication range could be obtained in telegraph mode, when information was transmitted by a telegraph key in Morse code or another discrete coding system. The frequency was stabilized by a removable quartz resonator; there was also a smooth frequency adjustment. 10RK-26 made it possible to simultaneously communicate at two fixed frequencies (with the abovementioned possibility of smooth adjustment); to change them, another quartz resonator of 8 pairs was used in the radio set.
The tank intercom TPU-4-BisF made it possible to negotiate between the crew members of the self-propelled guns even in a very noisy environment and connect a headset (headphones and laryngophones) to a radio station for external communication.

Soviet anti-tank self-propelled artillery of the ninth level. One of those machines that decide the outcome of a battle. The combination of decent speed, good camouflage and a powerful cannon makes you feel more than confident in any situation.

The last vehicle in the Soviet branch of anti-tank SPGs.

Modules

Compatible hardware

Compatible gear

Object 704 in play

Research and pumping

Object 704 Modules

The first thing literally necessary at Object 704, this is the new 152mm BL-10 cannon. The main thing is to study it on the ISU-152, because the stock Object 704 looks like a laughing stock on the battlefield. In addition, it can be easily installed without the Object 704M chassis, but they must be examined as soon as possible.

The next on the list will be the new V-2-54IS engine, since it can also be researched on the previous ISU-152. Without it, the self-propelled gun moves very slowly, at least it accelerates that way.

And the last two new radios are installed. With them, you can fire at great distances and keep abreast of events on the map.

Combat effectiveness

Pros and cons of Object 704:

Pros:

  • Amazing firepower and best armor penetration in the game.
  • Impressive tilt angles of the armor.
  • Decent speed.
  • Nice disguise.

Minuses:

  • Poor accuracy.
  • Weak booking of the sides and stern.
  • The smallest safety factor among tank destroyers of 9 tiers.

The main trump cards of the Object 704 are its striking firepower, excellent armor by the standards of a tank destroyer, and a high level of camouflage.

At correct use this self-propelled gun, you can destroy 3-6 tanks per battle. At the same time, it is not easy to finish off the last 5-15% of HP, as greedy companions do, but to quickly "disassemble" them from their one hundred percent state. All this thanks to the powerful BL-10 cannon. However, at long distances, it has big problems with accuracy.

The frontal armor of a self-propelled gun can be conditionally divided into 2 parts - a mask and an armor plate. The armor of the mask is 320mm, the reduced thickness of the armor plate is 187 mm. With proper luck (hitting the mask) Object 704 will not penetrate any armor-piercing shells. In addition, the large angles of inclination of the armor cause enemy shells to ricochet at a high frequency.

The main threat to Object 704 is high tier medium and light tanks. In close combat, they can "spin" the self-propelled guns, remaining unpunished. In this case, it is worth standing astern against a wall or other obstacle, depriving enemy vehicles of freedom of maneuver.

Equipment, consumables and ammunition

You can take 30 shells with you at Object 704. It is worth taking about 25, or even all 30 armor-piercing shells. The rest of the free space should be loaded with either sub-caliber or high-explosive, depending on the availability of gold.

The modules for Object 704 should be taken as follows:

Object 704 - Soviet tier 9 tank destroyer. The combination of the most powerful weapon, ricochet hull and excellent camouflage make you feel confident in any situation.

Pumping

  • Object 704 requires 176,500 experience points to research. Previous tank - ISU-152;
  • You can immediately install the BL-10 top gun on the stock chassis;
  • Exploring the top chassis. Thus, we increase the carrying capacity and swing speed;
  • Next, you need to investigate the engine. This will add power to us;
  • Last but not least, we study the radio.

Top-end equipment

How to play

This is a real tank destroyer with decent armor by the standards of a tank destroyer.

We have a sloping upper armor plate that gives ricochets and non-penetration, as well as a large gun mantlet, which is a devourer of enemy shells.

But, despite the strong forehead, you should not meddle in close combat. Firstly, we will be easily sorted out by focus, and, secondly, light or medium tanks will be able to calmly spin.

Remember that Object 704 is a clumsy, clumsy tank destroyer. She has a good top speed and is capable of taking up convenient positions to shoot off enemy troops.

The downside of the weapon is the long mixing. At long distances, the gun does not shine with accuracy, so we shoot when we are 100% sure of hitting.

There are two main tactics of application: attack, defense. In the first case, we fight over the backs of our allies and try not to receive damage, since because of our weapon we are a priority target for the enemy.

Our task is to smudge heavily armored tanks, leaving them to be devoured by allied ST and TT. In the second case, we stand behind a shelter or a bush and try to hold back the advancing enemy forces.

Advantages

  • Huge damage per shot;
  • High penetration;
  • Strong body forehead
  • Good stealth
  • Large UGN

Flaws

  • Weak booking of sides and stern;
  • Long reload and mixing
  • Poor agility

Crew skills and abilities

Equipment and gear

History reference

Object 704 was developed in 1945 using IS-2 and IS-3 components and assemblies. The tank destroyer was a fully armored vehicle with a forward conning tower.

The main armament was the 152-mm ML-20SM howitzer of the 1944 model. The rate of fire of the gun was 1–2 rounds per minute.

The height of the tank is 2240 mm. The decrease in height compared to the serial ISU-152 was achieved by increasing the width of the conning tower. The armor plates of the hull and wheelhouse were installed at large angles of inclination.

The combination of rational angles and impressive armor thickness provided the Object 704 with very high resistance to damage from enemy shells.

The "Object 704" also had its drawbacks. The lack of a muzzle brake on the ML-20SM gun led to an increase in the recoil of the barrel. Large angles of inclination of the armor reduced the inner space of the conning tower, so that the crew had to work in cramped conditions.

One copy of the machine was built and tested. The Object 704 was never put into mass production.



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